Tutorial ESWC2011 Building Semantic Sensor Web - 04 - Querying_semantic_streaming_data
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This document outlines an approach for enabling ontology-based access to streaming sensor data sources. It describes mapping streaming data to RDF using ontologies and enabling SPARQL queries over streaming RDF data. It provides examples of mapping sensor data streams and relational databases to ontologies using R2RML mappings. It also demonstrates executing continuous SPARQL queries over integrated streaming data sources using the Semantic Integrator system.
![SPARQLStream7Enabling Ontology-based Access to Streaming Data SourcesExample:“provide me with the wind speed observations over the last minute in the Solent Region ” PREFIX cd: <http://www.semsorgrid4env.eu/ontologies/CoastalDefences.owl#>PREFIX sb: <http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT ?waveheight ?wavetsFROM NAMED STREAM<http://www.semsorgrid4env.eu/waves.srdf> [ NOW – 1 MINUTE TO NOW – 0 MINUTES ] WHERE { ?WaveObs a cd:Observation; cd:observationResult ?waveheight; cd:observationResultTime ?wavets;cd:observedProperty ?waveProperty;cd:featureOfInterest ?waveFeature. ?waveFeature a cd:Feature;cd:locatedInRegioncd:SouthEastEnglandCCO. ?waveProperty a cd:WaveHeight. }cd:Observationcd:observationResultcd:observedPropertyxsd:doublecd:Propertycd:featureOfInterestcd:Featurecd:locatedInRegioncd:Region](https://image.slidesharecdn.com/04eswc11queryingstreamingdatathroughontologies-110608084113-phpapp02/85/Tutorial-ESWC2011-Building-Semantic-Sensor-Web-04-Querying_semantic_streaming_data-26-320.jpg)
![Standardize RDB2RDF mappings:BoscombeWaveHeight a rr:TriplesMapClass;rr:tableName "envdata_boscombe";rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#WaveHeight/CCO/{DateTime}";rr:classssn:ObservationValue; rr:graphssg:waves.srdf ];rr:predicateObjectMap [ rr:predicateMap [ rr:predicatessn:hasQuantityValue];rr:objectMap[ rr:column "Hs" ] ]; . <http://semsorgrid4env.eu/ns#/WaveHeight/CCO/2011-05-20:20:00 > a ssn:ObservationValue<http://semsorgrid4env.eu/ns#/WaveHeight/CCO/2011-05-20:20:00 > ssn:hasQuantityValue" 4.5"](https://image.slidesharecdn.com/04eswc11queryingstreamingdatathroughontologies-110608084113-phpapp02/85/Tutorial-ESWC2011-Building-Semantic-Sensor-Web-04-Querying_semantic_streaming_data-28-320.jpg)
![Query TranslationQueries: SELECT ?y WHERE{ ?x a cd:Observation; cd:observationResult ?y. }SELECT ?yFROM STREAM < STREAM <http://www.semsorgrid4env.eu/waves.srdf> [ NOW – 1 MINUTE TO NOW MINUTES ]>WHERE{ ?x a cd:Observation; cd:observationResult ?y. }](https://image.slidesharecdn.com/04eswc11queryingstreamingdatathroughontologies-110608084113-phpapp02/85/Tutorial-ESWC2011-Building-Semantic-Sensor-Web-04-Querying_semantic_streaming_data-29-320.jpg)
Tutorial ESWC2011 Building Semantic Sensor Web - 04 - Querying_semantic_streaming_data
- 1. Building SemanticSensorWebs and ApplicationsQuerying Streaming Data through OntologiesJean-Paul CalbimonteUniversidad Politécnica de MadridESWC TutorialHeraklion, 29 May 2011
- 8. Hands-onStreaming Data AccessSensor Data StreamsContinuously appended data
- 12. Changes of values over time
- 13. Latest used in queriesIntegration issuesHeterogeneous source
- 14. Knowledge about schemas and content
- 17. Motivation4Enabling Ontology-based Access to Streaming Data SourcesExpose sensor data as observations in terms of an Ontology
- 18. Achieve logical transparency in access to data.
- 19. Hide to the user where and how data are stored.
- 20. Present to the user a conceptual view of the data.
- 21. Use a semantically rich formalism for the conceptual view.
- 22. Need to provide solution for:
- 23. Establish mappings between ontological models and streaming data source schemas
- 24. Access streaming data sources through queries over ontology modelsOntology-based Streaming Data Access5Enabling Ontology-based Access to Streaming Data SourcesQueryTranslationSPARQLSreamalgebra(S1 S2 Sm) Sensor Network (S1)SPARQLStream(O1 O2On) q’Relational DB (S2)Distributed Query ProcessingStream-to-OntologymappingsClientStream Engine (S3)RDF Store (Sm)DataTranslationtriplestuplesOntology-based Streaming Data Access Service
- 25. SPARQLStream6Enabling Ontology-based Access to Streaming Data SourcesExample:“provide me with the wind speed observations over the last minute in the Solent Region ” ......( <si-1,pi-1, oi-1>, ti-1 ),( <si, pi, oi>, ti ),( <si+1,pi+1, oi+1>, ti+1),......RDF-StreamSTREAM <http://www.semsorgrid4env.eu/ccometeo.srdf>cd:Observation......( <ssg4e:Obs1,rdf:type, cd:Observation>, ti ),( <ssg4e:Obs1,cd:observationResult,”34.5”>, ti ),( <ssg4e:Obs2,rdf:type, cd:Observation>, ti+1),( <ssg4e:Obs2,cd:observationResult,”20.3”>, ti+1 ),......cd:observationResultxsd:double
- 26. SPARQLStream7Enabling Ontology-based Access to Streaming Data SourcesExample:“provide me with the wind speed observations over the last minute in the Solent Region ” PREFIX cd: <http://www.semsorgrid4env.eu/ontologies/CoastalDefences.owl#>PREFIX sb: <http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT ?waveheight ?wavetsFROM NAMED STREAM<http://www.semsorgrid4env.eu/waves.srdf> [ NOW – 1 MINUTE TO NOW – 0 MINUTES ] WHERE { ?WaveObs a cd:Observation; cd:observationResult ?waveheight; cd:observationResultTime ?wavets;cd:observedProperty ?waveProperty;cd:featureOfInterest ?waveFeature. ?waveFeature a cd:Feature;cd:locatedInRegioncd:SouthEastEnglandCCO. ?waveProperty a cd:WaveHeight. }cd:Observationcd:observationResultcd:observedPropertyxsd:doublecd:Propertycd:featureOfInterestcd:Featurecd:locatedInRegioncd:Region
- 27. R2RMLW3C RDB2RDF working group
- 28. Standardize RDB2RDF mappings:BoscombeWaveHeight a rr:TriplesMapClass;rr:tableName "envdata_boscombe";rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#WaveHeight/CCO/{DateTime}";rr:classssn:ObservationValue; rr:graphssg:waves.srdf ];rr:predicateObjectMap [ rr:predicateMap [ rr:predicatessn:hasQuantityValue];rr:objectMap[ rr:column "Hs" ] ]; . <http://semsorgrid4env.eu/ns#/WaveHeight/CCO/2011-05-20:20:00 > a ssn:ObservationValue<http://semsorgrid4env.eu/ns#/WaveHeight/CCO/2011-05-20:20:00 > ssn:hasQuantityValue" 4.5"
- 29. Query TranslationQueries: SELECT ?y WHERE{ ?x a cd:Observation; cd:observationResult ?y. }SELECT ?yFROM STREAM < STREAM <http://www.semsorgrid4env.eu/waves.srdf> [ NOW – 1 MINUTE TO NOW MINUTES ]>WHERE{ ?x a cd:Observation; cd:observationResult ?y. }
- 30. Query Translation10Mappings: queryalgebra expressionoversourcescd:Observationenvdata_milfordDatetime: longHs : floatLon: floatLat: floatcd:observationResultxsd:doubleDatetimeHsenvdata_milford
- 31. Query Translation11envdata_boscombeDatetime: longHs : floatLon: floatLat: floatUcd:Observationenvdata_milfordDatetime: longHs : floatLon: floatLat: floatcd:observationResultDateTimeHsUenvdata_hornseaxsd:doubleDatetime: longHs : floatLon: floatLat: floatUenvdata_westbayDatetime: longHs : floatLon: floatLat: floatDateTimeHsDateTimeHsDateTimeHsDateTimeHsenvdata_boscombeenvdata_milfordenvdata_hornseaenvdata_westbay
- 32. Query Translationvenvdata_westbayFeaturevenvdata_chesillocatedInRegionvenvdata_milfordObservationhasObservationResultR2RMappingvenvdata_hornseaStreamsOntologiesobservedPropertyenvdata_boscombeRegionxsd:floatTimestamp: longHs : floatLon: floatLat: floatWaveHeightPropertyPREFIX cd: <http://www.semsorgrid4env.eu/ontologies/CoastalDefences.owl#>PREFIX sb: <http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT ?waveheight ?wavetsFROM NAMED STREAM <http://www.semsorgrid4env/waves.srdf> WHERE { ?WaveObs a cd:Observation; cd:observationResult ?waveheight; cd:observationResultTime ?wavets;cd:observedProperty ?waveProperty;cd:featureOfInterest ?waveFeature. ?waveFeature a cd:Feature;cd:locatedInRegioncd:SouthEastEnglandCCO. ?waveProperty a cd:WaveHeight. }(SELECT timestamp,Hs FROM envdata_boscombe) UNION (SELECT timestamp,Hs FROM envdata_hornsea) UNION (SELECT timestamp,Hs FROM envdata_milford) UNION (SELECT timestamp,Hs FROM envdata_chesil) UNION (SELECT timestamp,Hs FROM envdata_perranporth) UNION (SELECT timestamp,Hs FROM envdata_westbay) UNION (SELECT timestamp,Hs FROM envdata_pevenseybay)SNEEqlSPARQLSTR
- 34. Semantic Integrator IQSR2RmappingsrepositoryIntegration Query ServiceIQSTranslatorIntegrationInterfaceSNEE-WSCCO-WSClientQueryInterfacePullInterfaceaddSourceIntegrateAs (DataResourceAddressList, R2R document)DataResourceAddress(SNEEql)addQuerySPARQLQueryFactory (DataResourceName, SPARQLSream )DataResourceAddressgetResultSetGetStreamNewestItem(DataResourceName )repeatDataSet
- 35. Hands-on 15Integrating and Querying streaming data through Ontologies
- 36. Use the SemSorGrid4Env Integration and Query Service (IQS)
- 37. Create an integrated resource from existing streams
- 38. Create a mapping document in R2RML
- 39. Use the IntegrateAs operation
- 40. Query the integrated resource
- 41. Write SPARQL-Stream queries over an ontology
- 42. Launch continuous queries (create a pull data resource)
- 43. Pull data periodically from a resourceDemoEnvironmentLocallyinstalled IQS:
- 45. Embedded SNEE query processor
- 46. Access the service through a Java console client:
- 50. WaveNet
- 51. Simulatedthrough a Java tuplegenerator:
- 54. Launch the Java console client:>cd /home/developer/iqs/iqs-client>java -cptarget/classes:target/dependency/* eu.semsorgrid4env.service.iqs.client.IntegrationServiceClientConnect to IQS:-connect http://localhost:9090/iqs-ws
- 55. Use Case: WavesatBoscombe?Wave data sources
- 56. CCO
- 57. WaveNet<streamname="envdata_boscombe" type="push"> <columnname="timestamp"> <type class="timestamp"/> </column> <columnname="stream_name"> <type class ="string"/> </column> <columnname="Hs"> <type class ="float"/> </column> <columnname="Tsea"> <type class ="float"/> </column> <columnname="Lat"> <type class ="float"/> </column> <columnname="Lon"> <type class ="float"/> </column> </stream>
- 58. Creating R2RML MappingsSimple mapping:
- 59. iqs/iqs-client/mappingSimple.ttl:boscombeWaveObsMapping a rr:TriplesMapClass;rr:SQLQuery ""; rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#Obs/WaveHeight/boscombe/{timestamp}";rr:classssn:Observation; rr:graphssg:waves.srdf];rr:tableName "envdata_boscombe";<http://semsorgrid4env.eu/ns#Obs/WaveHeight/bosocmbe/2011-05-20:20:00 > a ssn:Observation
- 60. Integrating the sourcesIntegrationInterfaceIQSClientIntegrateAs (DataResourceAddressList, R2R document)DataResourceAddressIntegrate configuration:iqs/iqs-client/integrate.propertiesintegrated.resource.name = obsResourceintegrated.resource.mapping = mappingSimple.ttlintegrated.resource.list = http://webgis1.geodata.soton.ac.uk:8080/CCO/services/PullStream?wsdl,http://webgis1.geodata.soton.ac.uk:8080/WaveNet/services/PullStream?wsdlIntegrate:-integrateintegrate.properties
- 64. Underlying data resourcesmappedthrough R2RML
- 66. Querying the new ResourceQueryInterfaceIQSClientSPARQLQueryFactory (DataResourceName, SPARQLStream )DataResourceAddressSamplequeryiqs/iqs-client/querySimple.sparqlSELECT ?obsWHERE { ?obs a ssn:Observation;}Launchcontinuousquery-queryquerySimple.sparqlobsResource
- 67. Pulling DataPullInterfaceIQSClientGetStreamNewestItem(DataResourceName )repeatDataSetPulling data from the new resource-pull obsResource1<?xml version="1.0" encoding="UTF-8" standalone="yes"?><sparqlxmlns="http://www.w3.org/2007/SPARQL/results#"> <head> <variable name="obs"/> </head> <results> <result> <bindingname="obs"> <uri>http://semsorgrid4env.eu/ns#Obs/WaveHeight/boscombe/1306497537858</uri> </binding>…..List pull resources-lp
- 68. TuplegeneratorLaunch the Tuplegenerator:>cd /home/developer/iqs/demo-client> java -cptarget/classes:target/dependency/* es.upm.fi.dia.oeg.integrator.client.TupleGenerator
- 69. More on MappingsAddingpredicates to the Observation:boscombeWaveObsMapping a rr:TriplesMapClass;rr:SQLQuery ""; rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#Obs/WaveHeight/boscombe/{timestamp}";rr:classssn:Observation; rr:graphssg:waves.srdf];rr:tableName "envdata_boscombe";rr:predicateObjectMap [rr:predicateMap [ rr:predicatessn:observationResult ]; rr:objectMap [ rr:column "Hs" ]], [rr:predicateMap [ rr:predicatessn:observationResultTime ]; rr:objectMap [ rr:column "timestamp" ]], [rr:predicateMap [ rr:predicatessn:observedProperty ]; rr:objectMap [ rr:objectcd:WaveHeight ]];.
- 70. CreateanotherIntegratedresourceIntegrate configuration, change resourcename:iqs/iqs-client/integrate.propertiesintegrated.resource.name = waveResourceintegrated.resource.mapping = mappingSimple.ttlintegrated.resource.list = http://webgis1.geodata.soton.ac.uk:8080/CCO/services/PullStream?wsdl,http://webgis1.geodata.soton.ac.uk:8080/WaveNet/services/PullStream?wsdlIntegrate:-integrateintegrate.properties
- 71. A more complex SPARQL querySamplequeryiqs/iqs-client/queryDemo.sparqlSELECT ?obs ?waveHeight ?wavetimeWHERE { ?obs a ssn:Observation;ssn:observationResult ?waveHeight; ssn:observedPropertycd:WaveHeight; ssn:observationResultTime ?wavetime. FILTER (?waveHeight > 0.2)}Launchcontinuousquery-queryqueryDemo.sparqlwaveResourcePull data-pull waveResource1
- 72. Mappingother Sources, otherPropertiesMore complexmapping:
- 74. The WaveNet Source: poolebaywave data::poolebayWaveObsMapping a rr:TriplesMapClass;rr:SQLQuery ""; rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#Obs/WaveHeight/poolebay/{timestamp}";rr:classssn:Observation; rr:graphssg:waves.srdf];rr:tableName "envdata_wavenet_poolebay";rr:predicateObjectMap [ rr:predicateMap [ rr:predicatessn:observationResult ]; rr:objectMap [ rr:column "Hs" ]], [ rr:predicateMap [ rr:predicatessn:observationResultTime ]; rr:objectMap [ rr:column "timestamp" ]], [ rr:predicateMap [ rr:predicatessn:observedProperty ]; rr:objectMap [ rr:objectcd:WaveHeight ]];.
- 76. Can query observations fromboth CCO and WaveNet
- 78. Mappingother Sources, otherPropertiesSeatemperature observations::boscombeTseaObsMapping a rr:TriplesMapClass;rr:SQLQuery ""; rr:subjectMap [ rr:template "http://semsorgrid4env.eu/ns#Obs/Temperature/boscombe/{timestamp}";rr:classssn:Observation; rr:graphssg:waves.srdf];rr:tableName "envdata_boscombe";rr:predicateObjectMap [ rr:predicateMap [ rr:predicatessn:observationResult ]; rr:objectMap [ rr:column "Tsea" ]], [ rr:predicateMap [ rr:predicatessn:observationResultTime ]; rr:objectMap [ rr:column "timestamp" ]], [ rr:predicateMap [ rr:predicatessn:observedProperty ]; rr:objectMap [ rr:objectcd:SeaTemperature ]];.
- 79. Modify the Query: GetTemperatureSamplequerySELECT ?obs ?value ?time WHERE { ?obs a ssn:Observation;ssn:observationResult ?value; ssn:observedPropertycd:SeaTemperature; ssn:observationResultTime ?time. FILTER (?value > 0.2)}Launchcontinuousquery-queryqueryDemo.sparqlnewResourcePull data-pull newResource2
- 80. Refining the output: RDF Observations ssn:isProducedByssn:SensorOutputssn:Sensorssn:observedByssn:observationResultssn:hasValuessn:Observationssn:ObservationValuessn:observesssn:featureOfInterestquantityValuessn:observedPropertyssn:FeatureOfInterestxsd:datatypessn:Propertyssn:hasProperty
- 81. ConstructQueriesSamplequeryCONSTRUCT { ?obs a ssn:Observation;ssn:observationResult [ a ssn:SensorOutput; ssn:hasValue [ a ssn:ObservationValue; ssg:hasQuantityValue ?waveHeight ]];ssn:observedPropertycd:WaveHeight; ssn:observationResultTime ?wavetime.}WHERE { ?obs a ssn:Observation;ssn:observationResult ?waveHeight; ssn:observedPropertycd:WaveHeight; ssn:observationResultTime ?wavetime. FILTER (?waveHeight > 0.9)}
- 82. Pull RDF ObservationsPull data-pull newResource5<rdf:Descriptionrdf:about="http://semsorgrid4env.eu/ns#Obs/WaveHeight/boscombe/1306624735493-1916241349527545207"> <j.1:observationResultTime>1306624735493</j.1:observationResultTime> <j.1:observedPropertyrdf:resource="http://www.semsorgrid4env.eu/ontologies/CoastalDefences.owl#WaveHeight"/> <j.1:observationResultrdf:nodeID="A2"/> <rdf:typerdf:resource="http://purl.oclc.org/NET/ssnx/ssn#Observation"/> </rdf:Description> <rdf:Descriptionrdf:nodeID="A2"> <j.1:hasValuerdf:nodeID="A1"/> <rdf:typerdf:resource="http://purl.oclc.org/NET/ssnx/ssn#SensorOutput"/> </rdf:Description> <rdf:Descriptionrdf:nodeID="A1"> <j.0:hasQuantityValue>0.9518465</j.0:hasQuantityValue> <rdf:typerdf:resource=http://purl.oclc.org/NET/ssnx/ssn#ObservationValue/> </rdf:Description>
- 83. Ontology-based Streaming Data QueryingSPARQL interface for Sensor data
- 84. User queries over the SSN Ontology
- 85. Transparently adding new sources
- 86. User unaware of underlying source schema details
- 87. Query translation mechanism and delegation of query execution to streaming data processor
- 88. Integrated virtual sources available for higher tier applications